Modern technologies make progresses day by day. Technological products continuously weed through the old to bring forth the new, particularly in wireless technological products such as cell phones or Bluetooth earphone. The Institute of Electrical and Electronics Engineers (IEEE) regulates many wireless network standards for avoiding interference, which would affect communication qualities, while using wireless products.
Besides, the Federal Communications Commission (FCC) has issued the First Report and Order on Ultra Wide Band (UWB) technology. The publication approved UWB technology in commercial deployment. A spectral mask is announced for ensuring UWB signals will not interfere frequency bands of other protocols, such as sensitive devices in Global Positioning System (GPS), and the Worldwide Interoperability for Microwave Access (WiMAX) protocol. In the spectral mask, there is a wide continuous bandwidth, in which the UWB communication technology adopts the bandwidth from 3.1GHz to 10.6 GHz with the effective isotropic radiated power (EIRP) emission limit being −41.25 dBmi/MHz.
However, because one of the frequency bands used by WiMAX includes the frequency of 3.6 GHz, the spectrum used by the WiMAX and the UWB protocols overlap. Thereby, the paper ECC/TG3 TG3#10_XX, “UWB Interference Mitigation”, 10thECC/TG3 meeting , Copenhagen, Jul. 2005 published by TI, which is related to interference avoidance technology, used Active Interference Cancellation (AIC) technology to achieve the purpose of interference avoidance. The capability of the notch filter for interference avoidance proposed by TI can reach approximately 30 dB. Nevertheless, such capability is still prone to interference.
Accordingly, a novel transmission system with interference avoidance and a method thereof that can improve the drawbacks of interference due to spectrum overlap are highly needed.